Talgil Computing and Control LTD RF-MODULE-45 사용자 설명서
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04
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DREAM
Layer 0
Layer 1
RTU
1
RTU
7
RTU
5
RTU
3
RTU
9
RTU
2
1
2
9
7
5
3
REPEATER
2.4.4 Setting up a repeater
When some RTUs have difficulty to communicate directly with the MASTER
because of a disturbing obstacle or too long distance, there is a necessity to use a
REPEATER. Both the RTU serving as a REPEATER and those using its services,
need to be informed about the arrangement. The following settings are required:
because of a disturbing obstacle or too long distance, there is a necessity to use a
REPEATER. Both the RTU serving as a REPEATER and those using its services,
need to be informed about the arrangement. The following settings are required:
SW3
- When SW3 is set to a nonzero value, the RTU becomes a REPEATER and
the value of SW3 represents the number of RTUs using the services of the
REPEATER. The number is expressed in binary notation (see Appendix A about
the binary to decimal conversion). For all the RTUs that are not repeaters, SW3
must be set to "0". In the example below, RTU No 2 is a repeater for 3 units
therefore switch SW3 of RTU No 2 should be set to 3.
Now the question is how does the REPEATER know exactly which RTUs it is
serving? The answer lies in the addresses of those RTUs. The first RTU must have
the address of the REPEATER +1, the second must have the address of the
REPEATER +3, the third will have the address of the REPEATER + 5 etc
REPEATER. The number is expressed in binary notation (see Appendix A about
the binary to decimal conversion). For all the RTUs that are not repeaters, SW3
must be set to "0". In the example below, RTU No 2 is a repeater for 3 units
therefore switch SW3 of RTU No 2 should be set to 3.
Now the question is how does the REPEATER know exactly which RTUs it is
serving? The answer lies in the addresses of those RTUs. The first RTU must have
the address of the REPEATER +1, the second must have the address of the
REPEATER +3, the third will have the address of the REPEATER + 5 etc
…
As mentioned above, all RTUs that are directly communicating with the MASTER,
without using a REPEATER, belong to layer "0". The RTUs that are functioning as
REPEATERS belong also to layer "0". Only the RTUs that are communicated via
REPEATERS are considered to belong to layer "1". Each of the units of layer "0"
occupy a single address,
but those who belong to layer “1” occupy 2 addresses,
therefore the immediately following address of such RTUs must be skipped.
Therefore RTUs that are communicating via repeaters differ from regular RTUs by
two things: first they belong to
Therefore RTUs that are communicating via repeaters differ from regular RTUs by
two things: first they belong to
layer “1” and second they occupy two addresses
instead of one.
Notice that the first RTU communicating through a repeater will get the
address immediately following the address of the REPEATER. The
other RTUs communicating via the REPEATER will have a gap of 1 from
the former RTU address.
There is no predefined limit to the number of REPEATERS that can be
used in an RF system. However the number of RTUs using the same
repeater is limited to 15.
address immediately following the address of the REPEATER. The
other RTUs communicating via the REPEATER will have a gap of 1 from
the former RTU address.
There is no predefined limit to the number of REPEATERS that can be
used in an RF system. However the number of RTUs using the same
repeater is limited to 15.
EXAMPLE
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The drawing shows a system
utilizing a repeater. There are 3 RTUs using
RTU No. 2 as a REPEATER, these units
belong to layer "1" while the REPEATER and
the other RTUs belong to layer “0”. The units
that communicate through the REPEATER
have the addresses "3", "5" and "7" and the
addresses "4", "6", "8" are skipped, they cannot
be used.
RTU No. 2 as a REPEATER, these units
belong to layer "1" while the REPEATER and
the other RTUs belong to layer “0”. The units
that communicate through the REPEATER
have the addresses "3", "5" and "7" and the
addresses "4", "6", "8" are skipped, they cannot
be used.